As is well known, personal computers are relatively small and inexpensive data processing systems primarily designed to provide a single user with independent computing power. Personal computers are available in a variety of sizes including desk-top, floor-standing, and portable models. A typical personal computer includes a system unit containing a microprocessor, a monitor, a printer, an internal hard disk drive, and a diskette drive. Specific examples are the different models of the IBM PS/2 personal computers. In contrast, larger, more expensive data processing systems such as the IBM System/370 computers, are characterized as "mainframe" systems and are primarily designed to provide computing power to multiple users. Mainframe systems have also been provided with relatively elaborate diagnostic systems which heretofore have been absent from personal computers.
Diagnostic systems are provided to increase the reliability, availability, and serviceability (RAS) of data processing systems. In general, diagnostic systems detect and analyze errors or faults that occur in the hardware and software portions of a data processing system while the system is being tested or operated. A diagnostic system in a mainframe system typically detects errors as they occur and logs such errors for later analysis by a diagnostic program. In contrast, diagnostic systems particularly for the above examples of personal computers, provide a narrow set of functions limited to displaying to the user a cryptic error code or message as errors are detected during a power on self test, or while the system is operating normally, or as a result of running a test or diagnostic program. The user is then left with the problem of deciding what the code or message means and what to do about it.
Another characteristic of mainframe systems is that they are closed systems having RAS features oriented to specific operating systems (OS). Status information is stored in distributed places at the hardware level and the particular operating system designed for the hardware "knows" where to go to obtain such information. There is no interface and the operating system directly accesses the desired information.